#include <stdio.h>

void swap1(int x, int y)
{
    int tmp = 0;
    tmp = x;
    x = y;
    y = tmp;
}

int main()
{

    int a = 10;
    int b = 20;
    int tmp = 0;

    printf("a=%d b=%d\n", a, b);
    swap1(a, b);
    printf("a=%d b=%d\n", a, b);

    return 0;
}
